3D printed medical devices including internal shaping

ABSTRACT

Systems and methods for manufacturing elongate medical devices including internal components embedded between multiple jacket layers. The system including a heating cartridge, a heating element, a filament handling system, a substrate handling system, and a controller to feed and melt each of the filaments for forming the multiple jacket layers. The system may include a single heating cartridge adapted to make multiple passes to form a first and second jacket or multiple heating cartridges that sequentially form a first and second jacket.

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 63/059,870 filed on Jul. 31, 2020, which isincorporated by reference herein in its entirety.

The disclosure generally relates to medical devices and, in particular,additive manufacturing or 3D printing of medical devices, such ascatheters and implantable stimulation leads.

Medical catheters and leads are commonly used to access vascular andother locations within a body and to perform various functions at thoselocations, for example, delivery catheters may be used to delivermedical devices, such as implantable medical leads. A number of suchmedical devices are designed to be navigated through tortuous paths in ahuman body, such as through a patient's vasculature. Medical cathetersand leads may be designed to be sufficiently flexible to move throughturns, or curves, in the vasculature yet sufficiently stiff, orresilient, to be pushed through the vasculature. In many cases, such asthose involving cardiovascular vessels, the route to the treatment ordeployment site may be tortuous and may present conflicting designconsiderations that may require compromises between dimensions,flexibilities, material selection, operational controls and the like.These contrasting properties can present challenges in designing andmanufacturing catheters. Existing manufacturing processes, such asconventional extrusion, may also limit options in designing andmanufacturing catheters.

SUMMARY

The techniques of the present disclosure generally relate to additivemanufacturing of medical devices, such as catheters and leads, thatallows for further customization of the medical devices by providing aneasier way to include components internal to the medical device. Forexample, the systems and techniques described herein may providedesigning and printing an initial layer with internal spaces forcomponents and then printing a finishing layer of the initial layer andcomponents. These systems and techniques may allow for manufacturingmore complex medical devices without increasing the complexity ofmanufacturing. Specifically, in one embodiment, the catheter may includeinternal grooves within which multiple lumen pull wires may be disposed.In another embodiment, the catheter may define an empty space for fluidtravel during balloon inflation and may, e.g., include a bumped surfaceto help support the outer jacket.

Additionally, the medical devices (e.g., such as catheters) may befurther customized through additive manufacturing to define lumenshaving a non-circular cross-sections (e.g., non-cylindrical shapes). Forexample, by utilizing systems and techniques described herein, acatheter jacket may be printed onto a combination of elongate substratesto define a lumen shape that corresponds to the combined elongatesubstrates. Specifically, two or more elongate substrates may becombined and arranged in a desired shape upon which the catheter jacketis printed to define the lumen having the desired shape. In someembodiments, a plurality of spacers may be used to separate the elongatesubstrates as desired. Further, the plurality of spacers may assist inthe removal of the elongate substrates after the catheter jacket isformed by additive manufacturing.

The details of one or more aspects of the disclosure are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the techniques described in this disclosurewill be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram of an illustrative additive manufacturingsystem according to the present disclosure.

FIG. 2 is a conceptual diagram of an illustrative additive manufacturingapparatus for use with, for example, the additive manufacturing systemof FIG. 1 .

FIG. 3 is a conceptual diagram of an illustrative heating cartridge foruse with, for example, the additive manufacturing system of FIG. 1 .

FIG. 4 is a conceptual diagram of an illustrative outlet die that may beused, for example, in the heating cartridge in the additivemanufacturing system of FIG. 1 .

FIG. 5 is a conceptual diagram of another illustrative outlet die thatmay be used, for example, in the heating cartridge in the additivemanufacturing system of FIG. 1 .

FIG. 6 is a conceptual diagram of an illustrative catheter jacket havinga first jacket and cutouts that may be manufactured using the additivemanufacturing system of FIG. 1 .

FIG. 7 is a conceptual diagram of another illustrative additivemanufacturing system according to the present disclosure.

FIG. 8 is a conceptual diagram of the illustrative catheter jacket ofFIG. 6 including pull wires and a second jacket using the additivemanufacturing system described herein.

FIG. 9 is cross-sectional conceptual diagram of the illustrativecatheter of FIG. 8 .

FIG. 10 is a cross-sectional conceptual diagram of another illustrativecatheter that may be manufactured using the additive manufacturingsystem of FIG. 1 .

FIG. 11 is a flow diagram that illustrates one example of a method foruse with, for example, the additive manufacturing system of FIG. 1 .

FIG. 12A is a perspective view of an illustrative catheter jacket havinga non-circular lumen through the catheter jacket according to thepresent disclosure.

FIG. 12B is a cross-sectional view of the catheter jacket of FIG. 12A.

FIG. 13A is a cross-sectional view of an illustrative assembly includingelongate substrates and spacers.

FIG. 13B is an exploded view of the assembly of FIG. 13A with elongatesubstrates spaced away from a spacer.

FIG. 14 is a cross-sectional view of another illustrative assemblyincluding elongate substrates and spacers.

FIG. 15 is a cross-sectional view of yet another illustrative assemblyincluding elongate substrates and spacers.

FIG. 16 is a flow diagram that illustrates one example of a method formanufacturing a catheter jacket having a non-circular lumen.

DETAILED DESCRIPTION

The present disclosure generally provides additive manufacturing systemsand methods for medical devices, such as catheters and leads, thatallows for providing more than one jacket or layer laid down to form themedical device. For example, one or more layers (e.g., an initial jacketor layer) may define shapes or structures within which internalcomponents may be positioned and subsequent layers or jackets may coveror embed the internal components. The internal shapes and componentsincluded may be dictated by desirable functional characteristics orproperties of the medical device. Specifically, components or emptyspace may be included on top of an initial print of filament material(e.g., a first layer or jacket) and a subsequent layer or jacket offilament material may be printed thereon. The printing may be done inmultiple stages or as a part of a co-print with multiple printing headand tools, as described herein.

As used herein, the term “or” refers to an inclusive definition, forexample, to mean “and/or” unless its context of usage clearly dictatesotherwise. The term “and/or” refers to one or all of the listed elementsor a combination of at least two of the listed elements.

As used herein, the phrases “at least one of” and “one or more of”followed by a list of elements refers to one or more of any of theelements listed or any combination of one or more of the elementslisted.

As used herein, the terms “coupled” or “connected” refer to at least twoelements being attached to each other either directly or indirectly. Anindirect coupling may include one or more other elements between the atleast two elements being attached. Either term may be modified by“operatively” and “operably,” which may be used interchangeably, todescribe that the coupling or connection is configured to allow thecomponents to interact to carry out described or otherwise knownfunctionality. For example, a controller may be operably coupled to aresistive heating element to allow the controller to provide anelectrical current to the heating element.

As used herein, any term related to position or orientation, such as“proximal,” “distal,” “end,” “outer,” “inner,” and the like, refers to arelative position and does not limit the absolute orientation of anembodiment unless its context of usage clearly dictates otherwise.

All scientific and technical terms used herein have meanings commonlyused in the art unless otherwise specified. The definitions providedherein are to facilitate understanding of certain terms used frequentlyherein and are not meant to limit the scope of the present disclosure.

Reference will now be made to the drawings, which depict one or moreaspects described in this disclosure. However, it will be understoodthat other aspects not depicted in the drawings fall within the scope ofthis disclosure. Like numbers used in the figures refer to likecomponents, steps, and the like. However, it will be understood that theuse of a reference character to refer to an element in a given figure isnot intended to limit the element in another figure labeled with thesame reference character. In addition, the use of different referencecharacters to refer to elements in different figures is not intended toindicate that the differently referenced elements cannot be the same orsimilar.

FIG. 1 shows one example of an additive manufacturing system 100according to the present disclosure. The system 100 may be configuredand used to produce a catheter, catheter component, lead, orsubassembly. The system 100 may use or include consumable filamentmaterials or pellet form resins having a wide variety of hardnesslevels. The system 100 may be configured to operate a wide variety ofprocess conditions to produce catheters, catheter components, leads, orsubassemblies using filaments or pellet form resins of various hardnesslevels. In general, the system 100 defines a distal region 128, ordistal end, and a proximal region 130, or proximal end. The system 100may include a platform 124 including a rigid frame to support one ormore components of the system.

Further components of the system 100 may be shown as described in U.S.Pat. App. No. 62/927,092, entitled “ADDITIVE MANUFACTURING FOR MEDICALDEVICES,” which is herein incorporated by reference. For example, asshown in the illustrated embodiment, the system 100 may include one ormore components, such as a heating cartridge 102, a heating element 104,a filament handling system 106, an optional wire handling system 107, asubstrate handling system 108, a controller 110, and a user interface112. The filament handling system 106 may be operably coupled to theheating cartridge 102. The filament handling system 106 may provide oneor more filaments 114 to the heating cartridge 102. The optional wirehandling system 107 may be used to provide one or more wires 115 to theheating cartridge 102. The heating element 104 may be operably coupled,or thermally coupled, to the heating cartridge 102. The heating element104 may provide heat to melt filament material in the heating cartridge102 from the one or more filaments 114 provided by the filament handlingsystem 106. The optional wires 115 may not be melted by the heatingcartridge 102. The substrate handling system 108 may be operably coupledto the heating cartridge 102. The substrate handling system 108 mayprovide a substrate 116 that extends through the heating cartridge.Melted filament material located in the heating cartridge 102 may beapplied to the substrate 116. The substrate 116 or the heating cartridge102 may be translated or rotated relative to one another by thesubstrate handling system 108. The substrate handling system 108 may beused to move the substrate 116 or the heating cartridge 102 relative toone another to cover the substrate 116 with the melted filament materialto form a jacket 118. The optional wires 115 may be incorporated intothe jacket 118 (e.g., molded into, bedded within, etc.). In one or moreembodiments, the wire handling system 107 may be replaced with anintermediate component system positioned proximate the heating cartridge102 and comprising one or more internal components (as will be describedfurther herein) to be incorporated into the jacket 118. The intermediatecomponent system may include a 3D printer, a robotic arm, a spool, etc.that positions or places the internal components at the desired locationon the jacket 118 (e.g., between layers, within channels, etc.).

The substrate 116 may also be described as a mandrel or rod. The jacket118 may be formed or deposited around the substrate 116. In someembodiments, the jacket 118 may be formed concentrically around thesubstrate 116. In one example, the jacket 118 is formed concentricallyand centered around the substrate 116.

When the system 100 is used to make a catheter or catheter component,the jacket 118 may be described as a catheter jacket. Some or all of thesubstrate 116 may be removed or separated from the jacket 118 and theremaining structure coupled to the jacket may form the catheter orcatheter component, such as a sheath. One example of a catheter that maybe formed by the system 100 is shown in FIG. 6 .

The substrate 116 may be formed of any suitable material capable ofallowing melted filament material to be formed thereon. In someembodiments, the substrate 116 is formed of a material that melts at ahigher temperature than any of the filaments 114. One example of amaterial that may be used to form the substrate 116 includes stainlesssteel.

The controller 110 may be operably coupled to one or more of the heatingelement 104, the filament handling system 106, the substrate handlingsystem 108, and the user interface 112. The controller 110 may activate,or initiate or otherwise “turn on,” the heating element 104 to provideheat to the heating cartridge 102 to melt the filament material locatedtherein. Further, the controller 110 may control or command one or moremotors or actuators of various portions of the system 100. Furthermore,the controller 110 may control one or more motors or actuators thefilament handling system 106 to provide one or more filaments 114.Further, the controller 110 may control one or more motors or actuatorsof the substrate handling system 108 to move one or both of the heatingcartridge 102 or the substrate 116 relative to one another. Furtherstill, the controller 110 may send or receive data to the user interface112, for example, to display information or to receive user commands.Control of the components operably coupled to the controller 110 may bedetermined based on user commands received by the user interface 112. Insome embodiments, the user commands may be provided in the form of amachine-readable code or coding language.

Any suitable implementation may be used to provide the substratehandling system 108. In some embodiments, the substrate handling system108 may include one or more of a head stock 120, an optional tail stock122, and one or more motors coupled to or included in the head stock ortail stock. One or both of the head stock 120 and the tail stock 122 maybe coupled to the platform 124. A stock may be defined as a structurethat holds or secures the substrate 116 during formation of the jacket118. The head stock 120 is defined as the stock closest to the end ofthe substrate 116 where formation of the jacket 118 begins in theformation process. In the illustrated embodiment, the jacket 118 isshown proximal to the head stock 120 and distal to the heating cartridge102.

When the substrate 116 is secured by one or both stocks 120, 122, thesubstrate is generally positioned to pass through a substrate channeldefined by the heating cartridge 102. One or both stocks 120, 122 mayinclude a clamp or other securing mechanism to selectively hold thesubstrate 116. Such a clamp may be operably coupled to a substratemotor. In some embodiments, the substrate motor may be used to controlopening and closing of the clamp. In some embodiments, the substratemotor may be used to rotate the substrate 116 in a clockwise orcounterclockwise direction about a longitudinal axis 126. A translationmotor may be operably coupled between a stock 120, 122 and the platform124. In some embodiments, the translation motor may be used to translatethe stock 120, 122 in a longitudinal direction along the longitudinalaxis 126. In some embodiments, the translation motor also may be used totranslate the stock 120, 122 in a lateral direction different than thelongitudinal axis 126. The lateral direction may be orientedsubstantially orthogonal, or perpendicular, to the longitudinal axis126.

In some embodiments, the substrate handling system 108 may be configuredto move the head stock 120 at least in a longitudinal direction (forexample, parallel to the longitudinal axis 126) relative to the platform124. The substrate 116 may be fed through the substrate channel of theheating cartridge 102 by movement of the head stock 120 relative to theplatform 124. A distal portion of the substrate 116 may be clamped intothe head stock 120. The head stock 120 may be positioned close to theheating cartridge 102 at the beginning of the jacket formation process.The head stock 120 may move distally away from the heating cartridge102, for example in a direction parallel to the longitudinal axis 126.In other words, the head stock 120 may move toward the distal region 128of the system 100 while pulling the secured substrate 116 through theheating cartridge 102. As the substrate 116 passes through the heatingcartridge 102, melted filament material from the filament 114 may beformed or deposited onto the substrate 116 to form the jacket 118. Theheating cartridge 102 may be stationary relative to the platform 124. Insome embodiments, the tail stock 122 may be omitted.

In some embodiments, the substrate handling system 108 may be configuredto move the heating cartridge 102 at least in a longitudinal direction(along the longitudinal axis 126) relative to the platform 124. Thesubstrate 116 may be fed through the substrate channel of the heatingcartridge 102. A distal portion of the substrate 116 may be clamped intothe head stock 120. A proximal portion of the substrate 116 may beclamped into the tail stock 122. In one example, the heating cartridge102 may be positioned relatively close to the head stock 120 at thebeginning of the jacket formation process. The heating cartridge 102 maymove proximally away from the head stock 120. The heating cartridge 102may move toward the proximal region 130 of the system 100. As theheating cartridge 102 passes over the substrate 116, melted filamentmaterial may be deposited onto the substrate 116 to form a jacket. Thehead stock 120 and the tail stock 122 may be stationary relative to theplatform 124. In another example, the heating cartridge 102 may startnear the tail stock 122 and move toward the distal region 128.

One or more motors of the substrate handling system 108 may be used torotate one or both of the substrate 116 and the heating cartridge 102relative to one another. In some embodiments, only the substrate 116 maybe rotated about the longitudinal axis 126. In some embodiments, onlythe heating cartridge 102 may be rotated about the longitudinal axis126. In some embodiments, both the substrate 116 and the heatingcartridge 102 may be rotated about the longitudinal axis 126.

The heating cartridge 102 may be part of a subassembly 132. Thesubassembly 132 may be coupled to the platform 124. In some embodiments,one or more motors of the substrate handling system 108 may be coupledbetween subassembly 132 and the platform 124 to translate or rotate thesubassembly 132, including the heating cartridge 102, relative to theplatform 124 or the substrate 116. In some embodiments, one or moremotors of the substrate handling system 108 may be coupled between aframe of the subassembly 132 and the heating cartridge 102 to translateor rotate the heating cartridge relative to the platform 124.

In some embodiments, the substrate 116 may be rotated about thelongitudinal axis 126 relative to the heating cartridge 102 tofacilitate forming certain structures of the jacket. In one example, thesubstrate 116 may be rotated by one or both of the head stock 120 andthe tail stock 122 of the substrate handling system 108. In anotherexample, the heating cartridge 102 or subassembly 132 may be rotated bythe substrate handling system 108.

The system 100 may include one or more concentricity guides 134. Theconcentricity guide 134 may facilitate adjustments to the concentricityof the jacket around the substrate 116 before or after the substratepasses through the heating cartridge 102. The concentricity guide 134may be longitudinally spaced from the heating cartridge 102. In someembodiments, the spacing may be greater than or equal to 1, 2, 3, 4, or5 cm. The spacing may be sufficient to allow the jacket 118 to cool downand no longer be deformable. In some embodiments, one or moreconcentricity guides 134 may be positioned distal to the heatingcartridge 102 and to engage the jacket 118. In some embodiments, one ormore concentricity guides 134 may be positioned proximal to the heatingcartridge 102 to engage the substrate 116. The concentricity guide 134may mitigate drooping of the substrate 116 and may mitigatesusceptibility to eccentricity in the alignment of the stock 120, 122and the heating cartridge 102.

Any suitable implementation may be used to provide the filament handlingsystem 106. One or more filaments 114 may be loaded into the filamenthandling system 106. For example, filaments 114 may be provided in theform of wound coils. Filaments 114 may be fed to the heating cartridge102 by the filament handling system 106. In some embodiments, thefilament handling system 106 may include one, two, or more pinch rollersto engage the one or more filaments 114. In some embodiments, thefilament handling system 106 may include one or more motors. The one ormore motors may be coupled to the one or more pinch rollers to controlrotation of the pinch rollers. The force exerted by the motors onto thepinch rollers and thus onto the one or more filaments 114 may becontrolled by the controller 110.

In some embodiments, the filament handling system 106 may be configuredto feed the filaments 114 including at least a first filament and asecond filament. The jacket 118 may be formed from the material of oneor both of the filaments 114. The filament handling system 106 may becapable of selectively feeding the first filament and the secondfilament. For example, one motor may feed the first filament and anothermotor may feed the second filament. Each of the motors may beindependently controlled by the controller 110. Selective, orindependent, control of the feeds may allow for the same or differentfeed forces to be applied to each of the filaments 114.

The filaments 114 may be made of any suitable material, such aspolyethylene, PEBAX elastomer (commercially available from Arkema S.A.of Colombes, France), nylon 12, polyurethane, polyester, liquid siliconerubber (LSR), or PTFE.

The filaments 114 may have any suitable Shore durometer. In someembodiments, the filaments 114 may have, or define, a Shore durometersuitable for use in a catheter. In some embodiments, the filaments 114have a Shore durometer of at least 25 A and up to 90 A. In someembodiments, the filaments 114 have a Shore durometer of at least 25 Dand up to 80 D.

In some embodiments, the filament handling system 106 may provide a softfilament as one of the filaments 114. In some embodiments, a softfilament may have a Shore durometer less than or equal to 90 A, 80 A, 70A, 80 D, 72 D, 70 D, 60 D, 50 D, 40 D, or 35 D.

In some embodiments, the filament handling system 106 may provide a hardfilament and a soft filament having a Shore durometer less than the softfilament. In some embodiments, the soft filament has a Shore durometerthat is 10D, 20 D, 30 D, 35 D, or 40 D less than a Shore durometer ofthe hard filament.

The system 100 may be configured to provide a jacket 118 between theShore durometers of a hard filament and a soft filament. In someembodiments, the filament handling system 106 may provide a hardfilament having a Shore durometer equal to 72 D and a soft filamenthaving a Shore durometer equal to 35 D. The system 100 may be capable ofproviding a jacket 118 having a Shore durometer that is equal to orgreater than 35 D and less than or equal to 72 D.

The system 100 may be configured to provide a jacket 118 having, ordefining, segments with different Shore durometers. In some embodiments,the system 100 may be capable of providing a jacket 118 having one ormore of a 35 D segment, a 40 D segment, 55 D segment, and a 72 Dsegment.

The filaments 114 may have any suitable width or diameter. In someembodiments, the filaments 114 have a width or diameter of 1.75 mm. Insome embodiments, the filaments 114 have a width or diameter of lessthan or equal to 1.75, 1.5, 1.25, 1, 0.75, or 0.5 mm.

Segments may have uniform or non-uniform Shore durometers. The system100 may be configured to provide jacket 118 having one or more segmentswith non-uniform Shore durometers. In some embodiments, the jacket 118may include continuous transitions between at least two different Shoredurometers, for example, as shown in FIG. 6 .

The controller 110 may be configured to change a feeding force appliedto one or more of the filaments 114 to change a ratio of material in thejacket over a longitudinal distance. By varying the feeding force, thesystem 100 may provide different Shore durometer segments in a jacket118, whether uniform or non-uniform. In one example, sharp transitionsbetween uniform segments may be provided by stopping or slowinglongitudinal movement while continuously, or discretely with a largestep, changing the feeding force of one filament relative to anotherfilament of the substrate 116 relative to the heating cartridge 102. Inanother example, gradual transitions between segments may be provided bycontinuously, or discretely with small steps, changing the feeding forceof one filament relative to another filament while longitudinally movingthe substrate 116 relative to the heating cartridge 102.

The one or more wires 115 provided by the wire handling system 107 maybe introduced in any suitable manner. In some embodiments, the wires 115may be attached to the substrate 116 and pulled by movement of thesubstrate. One example of a wire is a pull wire that may be used tosteer the catheter produced by the system 100. In some embodiments, aparticularly shaped heating cartridge may be used to accommodate one ormore wires 115.

Any suitable type of heating element 104 may be used. In someembodiments, the heating element 104 may be a resistive-type heatingelement, which may provide heat in response to an electrical current.Other types of heating elements that may be used for the heating element104 include a radio frequency (RF) or ultrasonic-type heating element.The heating element 104 may be capable of providing heat sufficient tomelt the filaments 114. In some embodiments, the heating element 104 mayheat the filaments 114 to greater than or equal to 235, 240, 250, or 260degrees Celsius. In general, the one or more heating elements 104 may beused to heat the filaments 114 to any suitable melting temperature knownto one of ordinary skill in the art having the benefit of thisdisclosure.

FIG. 2 shows one example of an additive manufacturing apparatus 200 ofthe additive manufacturing system 100 in an end view along thelongitudinal axis 126, which is illustrated as a circle and cross. Moredetail of some components of the additive manufacturing system 100 areshown, such as the heating cartridge 102 and the filament handlingsystem 106.

The heating cartridge 102 may include a heating block 202 at leastpartially defining an interior volume 204. The interior volume 204 maybe heated by the heating element 104. The heating element 104 may bethermally coupled to the heating block 202 to melt filament material inthe interior volume 204. In general, the system 100 may be configured tomelt any portion of the filaments 114 in the interior volume 204. Theheating element 104 may be disposed in an exposed or exterior volumedefined in the heating block 202. The heating element 104 may bepositioned proximate to or adjacent to the interior volume 204. In someembodiments, one, two, three, or more heating elements 104 may bethermally coupled to the heating block 202.

The heating block 202 may allow the substrate 116, which may be anelongate substrate or member, to pass through the heating block. Thesubstrate 116 may be able to extend, or pass, through the interiorvolume 204. The substrate channel 206 defined by the heating cartridge102 may extend through the interior volume 204. The substrate channel206 may extend in a same or similar direction as the substrate 116. Thesubstrate channel 206 may extend along the longitudinal axis 126.

A width or diameter of the interior volume 204 is larger than a width ordiameter of the substrate 116. The width or diameter of the interiorvolume 204 or the substrate 116 is defined in a lateral direction, whichmay be orthogonal to the longitudinal axis 126. In one example, thelateral direction may be defined along a lateral axis 210. In someembodiments, the clearance between the substrate 116 and interior volume204 is relatively small to facilitate changes in composition of filamentmaterial used to form the jacket 118 (FIG. 1 ) around the substrate 116.

The portion of the interior volume 204 around the substrate 116 mayreceive a flow of melted filament material from the filaments 114. Whenmore than one filament material is provided to the interior volume 204,the filament materials may flow and blend, or mix, around the substrate116.

In the illustrated embodiment, the filaments 114 includes a firstfilament 212 and a second filament 214. The first filament 212 may beprovided into the interior volume 204 through a first filament port 216at least partially defined by the heating block 202. The second filament214 may be provided into the interior volume 204 through a secondfilament port 218 at least partially defined by the heating block 202.Each filament port 216, 218 may be at least partially defined by theheating block 202. Each filament port 216, 218 may be in fluidcommunication with the interior volume 204.

The filaments 114 may be delivered to the interior volume 204 in thesame or different manners. In the illustrated embodiment, the firstfilament 212 is delivered to the interior volume 204 in a differentmanner than the second filament 214.

The filament handling system 106 may include a first handlingsubassembly 220. The first handling subassembly 220 may deliver thefirst filament 212 to the interior volume 204. The first handlingsubassembly 220 may include one or more pinch rollers 222. Each of theone or more pinch rollers 222 may be operably coupled to a motor. Anysuitable number of pinch rollers 222 may be used. As illustrated, thefirst handling subassembly 220 may include two sets of pinch rollers222. Pinch rollers 222 may be used to apply a motive force to the firstfilament 212 to move the first filament, for example, toward theinterior volume 204.

The heating cartridge 102 may include a first guide sheath 224. Thefirst guide sheath 224 may extend between the filament handling system106 and the interior volume 204. The first guide sheath 224 may becoupled to the heating block 202. The first guide sheath 224 may extendinto the first filament port 216 from an exterior of the heating block202. The first guide sheath 224 may define a lumen in fluidcommunication with the interior volume 204. An inner width or diameterof the lumen may be defined to be greater than a width or diameter ofthe first filament 212. The first filament 212 may extend through thefirst guide sheath 224 from the pinch rollers 222 of the first handlingsubassembly 220 to the first filament port 216 and extend distally pastthe first guide sheath 224 into the interior volume 204.

As used herein with respect to the filaments 114, the term “distal”refers to a direction closer to the interior volume 204 and the term“proximal” refers to a direction closer to the filament handling system106.

In some embodiments, a proximal end of the first guide sheath 224 mayterminate proximate to one of the pinch rollers 222. A distal end of thefirst guide sheath 224 may terminate at a shoulder 226 defined by thefirst filament port 216. A distal portion or distal end of the firstguide sheath 224 may be positioned proximate to or adjacent to theinterior volume 204.

The inner width or diameter of the lumen of the first guide sheath 224may be defined to be substantially the same or equal to an inner widthor diameter of the first filament port 216, such as a smallest innerwidth or diameter of the first filament port. In other words, an innersurface of the first guide sheath 224 may be flush with an inner surfaceof the first filament port 216.

In some embodiments, the heating cartridge 102 may include a supportelement 228. The support element 228 may be coupled to the first guidesheath 224. The first guide sheath 224 may extend through a lumendefined by the support element 228. The support element 228 may beproximate to the heating block 202. In the illustrated embodiment, thesupport element 228 is coupled to the heating block 202. The supportelement 228 may include a coupling protrusion configured to bemechanically coupled to a coupling receptacle 230 defined by the firstfilament port 216. In some embodiments, the coupling receptacle 230 maydefine threads and the coupling protrusion of the support element 228may define complementary threads.

The coupling receptacle 230 may terminate at the shoulder 226 of thefirst filament port 216. The coupling protrusion of the support element228 may be designed to terminate at the shoulder 226. In someembodiments, a distal end of the support element 228 and the distal endof the first guide sheath 224 may engage the shoulder 226. In otherembodiments, the distal end of the support element 228 may engage theshoulder 226 and the distal end of the first guide sheath 224 may engagea second shoulder (not shown) defined by the first filament port 216distal to the shoulder 226.

When the first filament port 216 defines one shoulder, the firstfilament port 216 may define at least two different inner widths ordiameters. The larger inner width or diameter may be sized to thread thesupport element 228 and the smaller inner width or diameter may be sizedto match the inner width or diameter of the first guide sheath 224.

When the second filament port 218 defines two shoulders, the firstfilament port 216 may define at least three different inner widths ordiameters. The largest inner width or diameter may be sized to threadthe support element 228. The intermediate inner width or diameter may besized to receive a distal portion of the first guide sheath 224. Thesmallest inner width or diameter may be sized to match the inner widthor diameter of the first guide sheath 224.

The filament handling system 106 may include a second handlingsubassembly 232. The second handling subassembly 232 may deliver thesecond filament 214 to the interior volume 204. The second handlingsubassembly 232 may include one or more pinch rollers 222. Each of theone or more pinch rollers 222 may be operably coupled to a motor. Anysuitable number of pinch rollers 222 may be used. As illustrated, thesecond handling subassembly 232 may include one set of pinch rollers222. Pinch rollers 222 may be used to apply a motive force to the secondfilament 214.

The heating cartridge 102 may include one or more of a second guidesheath 234, a heat sink 236, and a heat break 238. The second guidesheath 234 may extend at least between the second handling subassembly232 and the heat sink 236. The second guide sheath 234 may be coupled tothe heat sink. The second guide sheath 234 may be coupled to the secondhandling subassembly 232. The heat sink 236 may be coupled to the heatbreak 238. The heat break 238 may be coupled to the heat block 202. Theheat break 238 may extend into the second filament port 218 from anexterior of the heating block 202.

The second guide sheath 234 may define a lumen in fluid communicationwith the interior volume 204. The second filament 214 may extend throughthe second guide sheath 234 from the second handling subassembly 232 tothe heat sink 236, through the heat sink 236, through the heat break,and through the second filament port 218. In some embodiments, thesecond guide sheath 234 may extend to the pinch rollers 22 in the secondhandling subassembly 232. In some embodiments, the second guide sheath234 may extend at least partially into the heat sink 236.

The heat break 238 may be proximate to the heating block 202. The heatbreak 238 may be positioned between the heat sink 236 and the heatingblock 202. The heat break 238 may include a coupling protrusionconfigured to mechanically couple to a coupling receptacle 240 definedby the second filament port 218. In some embodiments, the couplingreceptacle 240 may define threads and the coupling protrusion of theheat break 238 may define complementary threads. The second filamentport 218 may include one or more shoulders such as those described withrespect to the first filament port 216, except that the second filamentport 218 may not be configured to receive the second guide sheath 234.The inner width or diameter of the support element 228 may be largerthan the inner width or diameter of the heat break 238, for example, toaccommodate the outer width or diameter of the first guide sheath 224.In other embodiments, the second filament port 218 may be configured toreceive the second guide sheath 234 in a similar manner to the firstfilament port 216 receiving the first guide sheath 224.

Any suitable material may be used to make the guide sheaths 224, 234. Insome embodiments, one or both guide sheaths 224, 234 may include asynthetic fluoropolymer. One or both guide sheaths 224, 234 may includepolytetrafluoroethylene (PTFE). Another suitable material may include anultra-high molecular weight polyethylene (UHMWPE).

Any suitable material may be used to make the support element 228. Insome embodiments, the support element 228 may be a thermal insulator.The support element 228 may include a thermoplastic. The support element228 may be made of a polyamide-imide, such as a TORLON polyamide-imide(commercially available from McMaster-Carr Supply Co. of Elmhurst,Ill.). Other suitable materials may include liquid-crystal polymer,polyaryletherketone (PAEK), polyphenylene sulfide, and polysulfone.

The support element 228 may provide mechanical support to the firstguide sheath 224. The support element 228 may include a substantiallyrigid material. In some embodiments, the support element 228 include amaterial having a higher durometer than material used to make the firstguide sheath 224.

Any suitable material may be used to make the heat sink 236. The heatsink 236 may include a high thermal conductivity material. In someembodiments, the heat sink 236 includes aluminum.

Any suitable material may be used to make the heat break 238. The heatbreak 238 may include a low thermal conductivity material. In someembodiments, the heat break 238 includes titanium. The heat break 238may include a necked portion to reduce the amount of material between aproximal portion and a distal portion of the heat break. The neckedportion may facilitate a reduced thermal conductivity between theproximal portion and the distal portion of the heat break 238.

In general, use of the apparatus 200 may facilitate using softerfilaments at high feed forces and pressures, which tend to compress thesoft filament and may result in jamming. Using higher feed forces andpressures may allow for a greater range of process conditions and mayprovide a consistent jacket around the substrate. In particular, use ofthe first guide sheath 224 extending at least partially into the firstfilament port 216 may facilitate the use of softer filament and greater“push-ability.” Additionally, or alternatively, the use of the supportelement 228 may also facilitate the use of softer filament and greater“push-ability.” In other embodiments, the apparatus 200 may include ascrew or static mixer to help push a softer filament. In other words,the screw or static mixer may provide a cavity for softer filamentmaterial to be moved forward between the threads of the screw.

FIG. 3 shows a partial cross-sectional side view of one example of theheating cartridge 102. The heating cartridge 102 or the heating block202 may extend from a proximal side 410 to a distal side 412. In someembodiments, the heating cartridge 102 may include one or more of theheating block 202, an inlet die 402 coupled to the proximal side 410 ofthe heating block, an outlet die 404 coupled to the distal side 412 ofthe heating block, a proximal retaining plate 406 to facilitateretaining the inlet die adjacent to the heating block, and a distalretaining plate 408 to facilitate retaining the outlet die adjacent tothe heating block.

The inlet die 402 and the outlet die 404 may be retained in any suitablemanner. In the illustrated embodiment, the outlet die 404 may beretained by a distal shoulder of the distal retaining plate 408. In someembodiments, the inlet die 402 may be retained by the proximal retainingplate 406 between a distal shoulder of the proximal retaining plate 406and a fastener, such as a nut with a lumen extending through, which maybe threaded to the retaining plate to engage a proximal surface of theinlet die. The retaining plates 406, 408 may be fastened to the heatingblock 202 in any suitable manner.

The inlet die 402 may at least partially define a substrate inlet port414. The outlet die 404 may at least partially define a substrate outletport 416. The inlet die 402 may at least partially define the interiorvolume 204. The outlet die 404 may at least partially define theinterior volume 204. In some embodiments, an exterior surface of theinlet die 402, an interior surface of the outlet die 404, and aninterior surface of the heating block 202 may cooperatively define theinterior volume 204.

The substrate channel 206 may be described as extending from theproximal side 410 to the distal side 412 of the heating cartridge 102,or vice versa. The substrate channel 206 may extend through the interiorvolume 204. As shown, the substrate channel 206 may extend through oneor more of the proximal retaining plate 406, the inlet die 402, theheating block 202, the outlet die 404, and the distal retaining plate408.

FIG. 4 shows an end view of one example of an inlet or outlet die 700that may be used in the heating cartridge 102 (FIG. 1 ). The die 700 maydefine a substrate inlet or outlet port 702. The port 702 may define amain region 704 and one, two, three, four, or more cutouts 706, orcutout regions. In the illustrated embodiment, the port 702 defines fourcutouts 706.

When the interior cross-sectional shape die 700 is used in an outletdie, the jacket formed by the heating cartridge 102 may include a numberof protrusions corresponding to the number of cutouts 706 used in thedie 700. For example, the illustrated die 700 would produce fourprotrusions on the jacket.

In some embodiments, one or more of the cutouts 706 may be sized toreceive a wire 115 (FIG. 1 ), such as a pull wire, which may be providedby the wire handling system 107 (FIG. 1 ). In some embodiments, theinterior cross-sectional shape of die 700 may be used in both the inputdie and the outlet die to accommodate the wires 115 pulled through thecutouts 706.

FIG. 5 shows an end view one example of an inlet or outlet die 720 thatmay be used in the heating cartridge 102 (FIG. 1 ). The die 720 maydefine a substrate inlet or outlet port 722. The port 722 may define amain region 724 and one, two, three, four, or more protrusions 726, orcutout regions. In the illustrated embodiment, the port 722 defines twoprotrusions 726, or teeth.

When the interior cross-sectional shape die 720 is used in an outletdie, the jacket formed by the heating cartridge 102 may include a numberof channels corresponding to the number of protrusions 726 used in thedie 720. For example, the illustrated die 720 would produce two channelson the jacket.

The shape and feature of the outlet die 720 may control the shape andfeatures of a resultant first jacket 500. For example, as shown in FIG.6 , the first jacket 500 defines cutouts 504 in the outer surface 502 ofthe first jacket 500. The first jacket 500 may be similar to the jacket118 described herein, but may be the initial jacket that is formed andmay include geometrical features thereon (e.g., the cutouts 504) uponwhich a second jacket may be subsequently formed. The cutouts 504 may bea result of the corresponding outlet die through which the first jacket500 was formed. For example, the first jacket 500 of FIG. 6 defines foursymmetrical cutouts having a partially circular shape. Therefore, theoutlet die through which the first jacket 500 was formed included foursymmetrical protrusions that are semi-circular and extend towards thecenter of the opening of the outlet die. Further, the cutouts 504 mayextend along and parallel to the longitudinal axis 126 or may spiral orcorkscrew around the outer surface 502 of the first jacket 500. WhileFIG. 6 illustrates four symmetrical cutouts 504, the features definedwithin the first jacket 500 may be any suitable shape and/or size.

After forming the first jacket 500 including features as shown in FIG. 6, one or more internal components (e.g., a lumen, a pull wire, a liner,etc.) may be deposited on the first jacket 500 (e.g., within thefeatures defined in the first jacket 500). For example, the internalcomponents may be positioned within channels, between protrusions, orwithin protrusions formed in the first jacket. A pull wire 115 may beprovided by the wire handling system 107 (e.g., as shown in FIG. 1 ) andpositioned within the cutout 504. Specifically, the number of pull wiresmay correspond to the number of internal components formed on the firstjacket 500. As shown in FIG. 6 , there may be four pull wires positionedin the first jacket 500 (e.g., one pull wire in each cutout 504). Bypositioning the pull wires within the pre-formed cutouts 504, the pullwires may be more effectively and consistently spaced apart.

Thereafter, a second jacket may be formed around the first jacket 500and any internal components positioned therein. The second jacket may beformed similar to the first jacket 500 (or, e.g., as described herein asit pertains to the jacket 118) such as by feeding a second filament intothe interior cavity of the heating cartridge, melting the secondfilament within the interior cavity, and moving the heating cartridge toform the second jacket. Further, the second jacket may be formed usingthe same heating cartridge as the first jacket or a different heatingcartridge.

For example, in one or more embodiments, the heating cartridge 102 ofthe system 100 (e.g., as shown in FIG. 1 ) may make multiple passes(e.g., two) along the substrate to form each of the first and secondjackets. Once the heating cartridge 102 extends the length of thesubstrate 116 to form the desired length first jacket 500, the heatingcartridge 102 may return to the starting position and begin forming thesecond jacket. In other words, a first filament may be fed into andmelted within the interior cavity of the heating cartridge 102 to formthe first jacket and a second filament may be fed into and melted withinthe interior cavity of the same heating cartridge 102 to form the secondjacket. In such embodiments, the first and second filaments may be thesame filament being fed into the heating cartridge 102 (e.g., if theheating cartridge 102 only includes a single filament port). Although insome embodiments, as described herein, the heating cartridge 102 mayinclude at least two filament ports. Therefore, the first jacket may beformed from a first filament and the second jacket may be formed from asecond filament different than the first filament. In one or moreembodiments, the first and second jackets may be formed from anycombination of both the first and second filaments.

Also, as shown in FIG. 7 , the system 101 may include an additionalheating cartridge 103 that is distal to or trailing the heatingcartridge 102. Specifically, the additional heating cartridge 103 may belongitudinally spaced (e.g., along the longitudinal axis 126) apart fromthe heating cartridge 102. The system 101 may include all of the samecomponents as system 100 described in combination with FIG. 1 , butinclude the additional heating cartridge 103. Further, the additionalheating cartridge 103 may include all of the same features as theheating cartridge 102, but may be physically separate from the heatingcartridge 102. In such embodiments, the heating cartridge 102 may formthe first jacket and the additional heating cartridge 103 maysubsequently form the second jacket around the first jacket. Forexample, the heating cartridge 102 may define a first filament port influid communication with the interior volume to receive the firstfilament and the additional heating cartridge 103 may define a secondfilament port in fluid communication with the interior volume of theadditional heating cartridge to receive the second filament.

Even though the heating cartridges are separate components, the firstand second filament may include a same or different filament material.Further, each of the heating cartridge 102 and the additional heatingcartridge 103 may include two or more filament ports such that thejacket may be formed from a mixture of materials. As described herein,by combining filament materials into a single jacket, thecharacteristics (e.g., the flexibility) of the jacket may be customized.The one or more pull wires located within the catheter (e.g., betweenthe first and second jacket) may produce varying types of movement ofthe catheter depending on the characteristics of the material mixture ofthe first and second jackets. For example, if the second jacket (e.g.,outer jacket) is stiffer than the first jacket (e.g., inner jacket), thepull wires may provide greater range of motion.

As shown in each of FIGS. 1 and 7 , the wire handling system 107 (whichmay include the one or more pull wires) may feed the pull wires 115through the heating cartridge 102 to be positioned along the catheter.When the system 100 (e.g., as shown in FIG. 1 ) includes a singleheating cartridge 102 making multiple passes, the pull wire 115 may bepositioned after the first jacket is formed and prior to the secondjacket being formed. When the system 101 (e.g., as shown in FIG. 7 )includes a heating cartridge 102 and an additional heating cartridge103, the pull wire 115 may be configured to be positioned between theheating cartridge 102 and the additional heating cartridge 103 (e.g.,between the formation of the first and second jackets).

FIG. 8 shows one example of a catheter 600 that may be manufacturedusing the system 100 before the substrate 116 is removed. The substrate116 may include a lubricious coating on its exterior surface tofacilitate removal. The lubricious coating may extend around thecircumference of the substrate 116. One example of a lubricious coatingis a PTFE coating.

The substrate 116 may be covered with a liner 602, such as a PTFE layer.The liner 602 may be placed over the lubricious coating. The liner 602may extend around the circumference of the substrate 116.

The liner 602 may be covered with a braid 604, such as a stainless-steelbraid layer. The braid 604 may be placed over the liner 602. The braid604 may extend around the circumference of the liner 602. The braid 604may be porous.

The first jacket 500 may be applied to the braid 604. When the firstjacket 500 is formed, the liner 602 may adhere to the first jacket 500through pores in the braid 604.

As described herein the first jacket 500 may be formed with one or morecutouts (e.g., see FIG. 6 ). As shown in FIG. 8 , the cutouts are filledwith pull wires 115 extending along the length of the catheter 600.

Thereafter, the second jacket 510 may be formed around the first jacket500 and the pull wires 115.

In the illustrated embodiments, the catheter 600 includes a firstsegment 606, a second segment 608, and a third segment 610. Each segment606, 608, 610 may have different durometers. In some embodiments, thefirst segment 606 may have a high durometer, the third segment 610 mayhave a low durometer, and the second segment 608 may have a continuouslyvarying durometer in a longitudinal direction between the durometers ofthe first and third segments. For example, the first segment 606 mayhave a Shore durometer equal to 72 D, the third segment 610 may have aShore durometer equal to 35 D, and the second segment 608 may have aShore durometer that gradually changes from 72 D to 35 D over itslength. Further, the first and second jackets 500, 510 may have the sameor differing profiles extending along the longitudinal direction.

FIG. 9 illustrates the catheter 600 of FIG. 8 from the conceptualcross-sectional view and without the substrate 116 positioned therein.As described herein, the first jacket 500 is formed around the braid 604and the liner 602. The pull wires 115 are positioned within a portion ofthe first jacket 500 and surrounded by a liner 512 (e.g., a PTFE pullwire liner). The second jacket 510 may be formed around the first jacket500 and the pull wire liners 512. The pull wires 115 may besymmetrically positioned around and embedded in the catheter 600. Theprocess of embedding internal components as described herein may assistin easily spacing those internal components in a concentric way that maybenefit mechanical properties and physician handling (e.g., moving thepull wires).

Furthermore, other types of medical devices may be formed using themultiple jacket processes described herein. For example, FIG. 10illustrates a cross-sectional view of a balloon catheter 520 defining anempty space lumen 525 as an internal component. Specifically, thecatheter 520 may include a first liner 522 extending around thesubstrate (not shown). A first braid 524 may be positioned around thefirst liner 522 and a first jacket 500 may be formed on the first braid524.

Next, a second liner 526 may be positioned to include an empty space 525between the first jacket 500 and the second liner 526. In one or moreembodiments, the first jacket 500 may include surface features (e.g.,bumps, grooves, channels, etc.) such that the second liner 526 does notcompletely enclose the empty space 525. In other words, the surfacefeatures on the first jacket 500 may support the second jacket 510 abovethe first jacket 500. Further, in one or more embodiments, the materialsof the first jacket 500 and the second liner 526 (or, e.g., the secondjacket 510 formed thereon) may be selected such that the materials mayrepel (e.g., not fuse together) and separate when a fluid flows into theempty space 525.

In one or more embodiments, a second braid 528 may surround the secondliner 526 and the second jacket 510 may be formed thereon. Further, aballoon 530 may surround the second jacket. Therefore, the empty space525 may be used as a fluid channel or gap to inflate the balloon 530using, e.g., air or saline.

FIG. 11 shows one example of a method 800 of using the systems 100, 101(FIGS. 1 and 7 ) for additive manufacturing. The method 800 may be usedto manufacture an implantable medical device.

The method 800 may include feeding the substrate 802, for example,through a substrate channel in one or more heating cartridges. Thesubstrate channel may be in fluid communication with an interior cavityof the heating cartridge.

The method 800 may include feeding at least a first filament 804 througha filament port of the heating cartridge into the interior cavity.

The method 800 may include melting the first filament 806, for example,in the interior cavity. Any portion of the filaments contained in theinterior cavity may be melted.

The method 800 may include moving the heating cartridge relative to thesubstrate 808, for example, at least in a longitudinal direction to forma first jacket comprising material from at least the first filament. Theheating cartridge or substrate may also be rotated relative to oneanother. The jacket may be formed from material of at least the firstfilament. In some embodiments, the jacket may be formed from material ofat least the first filament and the second filament. In one or moreembodiments, the outlet die may form various surface features within theouter surface of the first jacket.

For example, in one or more embodiments, forming the first jacket mayinclude defining one or more protrusions extending from an outer surfaceof the first jacket. In one or more embodiments, forming the firstjacket may include defining one or more channels or cutouts extendinginward from an outer surface of the first jacket.

The method 800 may also include depositing one or more internalcomponents 810 on the first jacket (e.g., relative to the featuresformed on the surface of the first jacket). For example, the one or morecomponents may be deposited between the one or more protrusions orwithin the one or more channels.

The method 800 may include feeding at least a second filament 812through a filament port of the heating cartridge into the interiorcavity and melting the second filament 814 in the interior cavity of theone or more heating cartridges.

The method 800 may include moving the heating cartridge relative to thesubstrate 816, for example, at least in a longitudinal direction to forma second jacket comprising material from at least the second filament.The heating cartridge or substrate may also be rotated relative to oneanother. The jacket may be formed from material of at least the secondfilament. In some embodiments, the jacket may be formed from material ofat least the first filament and the second filament.

As described herein, the first and second jackets may be formed by asingle heating cartridge making multiple passes along the substrate orby two separate heating cartridges that are spaced apart from oneanother.

Additionally, the present disclosure generally provides additivemanufacturing systems and methods for medical devices, such ascatheters, that allows for providing a lumen extending through themedical device with a non-circular cross-sectional shape. For example,two or more elongate substrates may be arranged relative to one anotherto define the shape of the lumen and the catheter jacket may be printedthereon. This concept allows for specialty shapes through the fulllength of the catheter, and may allow for new technologies andadvancements in catheter research

Traditional catheters often use a cylindrical lumen or circularcross-section inside the catheter body and designs that requirenon-cylindrical (or non-circular cross-section) lumen features may useexpensive and time-consuming tooling. For example, custom machined diesand tooling may create a “neckable” core rod (e.g., copper) that isneeded to create a non-cylindrical lumen feature. Specifically, thetraditional lumen design may include a neckable silicone coated ethylenetetrafluoroethylene (ETFE) wire and copper core material. The copperwire core may age harden and reduce the amount of elongation beforebreaking (i.e., creating a shelf life for the copper core material).Further, the traditional catheter having a non-cylindrical ornon-circular lumen may require a SPCC machine to aid in core removalbecause as the lumen size increases, so too does the force required toremove the core from the catheter body (e.g., sizes greater than 0.08″may be extremely difficult to remove).

However, as described herein, an illustrative catheter having anon-cylindrical lumen feature may be manufactured using conventionalmandrels or elongate substrates and 3D printing technologies to print acatheter jacket thereon. For example, the conventional mandrels orelongate substrates may be arranged relative to another to create anon-cylindrical lumen feature (e.g., after a catheter jacket is printedthereon and the elongate substrates are removed therefrom). Thenon-cylindrical or non-circular lumen feature (e.g., created frommultiple mandrels or elongate substrates) may extend through the entirelength of the catheter shaft. Therefore, a variety of differentnon-cylindrical lumen features may be created without needing specialtooling to create an elongate substrate in the non-cylindrical shape.

Further, the elongate substrates that are combined to define thenon-cylindrical or non-circular lumen may be independently removed toease the removal process (e.g., compared to removing the entirecore/substrate at the same time) by not requiring the use of specialequipment. For example, elongate substrates having a cylindrical profilemay be easier to remove than a substrate or core having a differentshape profile. In other words, by using multiple substrates having acylindrical profile to form a non-cylindrical shape, the multiplesubstrates may be more easily removed than a single substrate having thenon-cylindrical shape. Further, the user of spacers (as describedherein) may also make removal of the elongate substrates easier.

FIG. 12A illustrates one example of a catheter jacket 300 having a lumenwith a non-circular cross-section and formed using additivemanufacturing as described herein. For example, two or more elongatesubstrates 310 may be positioned relative to one another to define theprofile of the lumen extending through the catheter jacket 300 createdby additive manufacturing. For example, as shown in FIG. 12A, twoelongate substrates 310 may be positioned relative to one another with aplurality of spacers 320 between the elongate substrates 310 to define anon-cylindrical (or non-circular cross-sectional) shape that forms thelumen. The assembly of the two elongate substrates 310 and the pluralityof spacers 320 therebetween may be covered with a liner 302 (e.g., tofill any potential gaps between the elongate substrates 310 and thespacers 320).

As described herein, the elongate substrates 310 define a cylindricalshape having a diameter and length, and may be described as mandrels orcores. The elongate substrates 310 may define any suitable size toachieve the desired lumen shape. For example, in one or moreembodiments, the elongate substrates 310 may define a diameter of about0.074″. In some embodiments, the elongate substrates 310 may define avariety of different sizes that are combined to form a desired lumenprofile/shape (e.g., as shown in FIG. 14 ). Further, the elongatesubstrates 310 may extend for the entire length of the catheter jacket300 (e.g., to form a lumen extending through the entirety of thecatheter). Additionally, the elongate substrates 310 may include (e.g.,be formed of) any suitable materials. For example, the elongatesubstrates 310 may include PTFE, coated steel, 3D printed plastic, etc.

In one or more embodiments, the elongate substrates 310 may be spacedapart from one another by a plurality of spacers 320 (e.g., as shown inFIGS. 12A and 12B). The plurality of spacers 320 may be specificallycreated (e.g., using 3D printing) and sized to correspond to thearrangement of the elongate substrates 310. For example, the pluralityof spacers 320 may define features (e.g., curved surfaces) thatcorrespond to the outer surface of the elongate substrates 310 toposition the elongate substrates 310 in the desired arrangement.

The plurality of spacers 320 may be spaced apart from one another alongthe longitudinal direction 301. For example, there may be gaps betweeneach spacer 320. These gaps between adjacent spacers 320 may assist inremoving the elongate substrates 310 after the catheter jacket 300 isprinted or formed over the elongate substrates 310. For example, byproviding gaps between the spacers 320, the amount of friction betweenthe printed catheter jacket 300 and the spacers 320 (e.g., to remove thespacers 320 and the elongate substrates 310) is reduced (e.g., ascompared to if the spacer extended the full length of the catheter). Assuch, having the plurality of spacers 320 spaced apart along thelongitudinal direction 301 still assists in maintaining the properspacing between the elongate substrates 310 while also reducing theamount of force needed to remove the elongate substrates 310 and thespacers 320. For example, in one or more embodiments, each spacer 320may define a length 322 of about 20 mm to 40 mm (e.g., measured alongthe longitudinal direction 301) and may be spaced apart from adjacentspacers 320 by a distance 324 of about 1 mm to 100 mm (e.g., measuredalong the longitudinal direction 301). It is noted that the ratio ofspacer length 322 to distance 324 between spacers 320 may vary dependingon the size/shape and arrangement of the elongate substrates. Forexample, in some embodiments, the elongate substrates may be moresupported by the spacers 320 (e.g., longer spacers 320 and/or spacers320 closer together) or less supported by the spacers 320 (e.g., shorterspacers 320 and/or spacers 320 farther apart).

The plurality of spacers 320 may include (e.g., be formed of) anysuitable material. For example, the plurality of spacers 320 may includeacrylic based resin that is ultraviolet (UV) cured (e.g., through 3Dprinting), Form labs Rigid 10K, Form labs High Temp V2, etc. Further,the plurality of spacers 320 may be created or formed in any suitableway. For example, the plurality of spacers 320 may be created usinginjection molding (e.g., plastic), machining, 3D printing, metalinjection molding (MIM), etc.

Furthermore, in one or more embodiments, a liner 302 may cover theelongate substrates 310 and the plurality of spacers 320. For example,the liner 302 may assist in keeping the elongate substrates 310 in thecorrect position relative to the spacers 320. Further, the liner 302 mayprovide smooth transitions between the multiple elongate substrates 310.For example, when the catheter jacket 300 is printed onto the elongatesubstrate 310, the filament material positioned and melted thereon mayconform to the shape of the elongate substrate 310. However, thepresence of the liner 302 between the elongate substrates 310 creates asmooth transition between the elongate substrates 310 (e.g., so thefilament material does not print into the gaps and crevasses locatedbetween the elongate substrates 310 and spacers 320). The liner 302 mayinclude (e.g., be formed of) any suitable material. For example, theliner 302 may include an etched PTFE material. Further, in one or moreembodiments, the liner 302 may be coated with a material or substance toassist with removal of the elongate substrates 310 after the catheterjacket is printed thereon.

As shown in FIGS. 13A, 14, and 15 , the resulting lumen formed from theelongate substrates 310 may define a variety of different shapes. Forexample, the two elongate substrates 310 and spacer 320 define an oblongshape in FIG. 13A. As shown in FIG. 13B, the spacer 320 defines anappropriate size and shape to receive the elongate substrates 310 onopposing sides (e.g., the spacer 320 defines cutouts that correspond tothe outer surface of the elongate substrates 310). Further, as shown inFIG. 13A, a liner 302 covers and wraps around the two elongatesubstrates 310 and spacers 320 therebetween.

FIG. 14 illustrates two different size elongate substrates 310 arrangedto define a diamond shape to form the lumen of the catheter jacket 300.For example, the elongate substrates 310 may include a first elongatesubstrate 311 and a second elongate substrate 312. The first elongatesubstrate 311 may define a cross-sectional diameter that is differentthan a cross-sectional diameter of the second elongate substrate 312. Asshown in FIG. 14 , the assembly may include two elongate substrates 310having the first elongate substrate 311 diameter and two elongatesubstrates having the second elongate substrate 312 diameter. The spacer320 is positioned between each of the elongate substrates 310. The liner302 covers each of the elongate substrates 310 to define a roundeddiamond shape, which will form the lumen of the catheter jacket 300.

FIG. 15 illustrates three elongate substrates 310 having the samediameter and arranged relative to one another with a spacer 320therebetween to form a rounded triangle shape. The liner 302 covers theelongate substrates to form the shape of the resulting lumen of thecatheter jacket 300. It is noted that the liners 302 of FIGS. 13A, 14,and 15 are illustrated as spaced apart from the elongate substrates 310,however, the spaced apart gaps are for illustrative/viewability purposesand the liners 302 may actually be in contact and wrap around theelongate substrates 310.

Any number and size of elongate substrates 310 may be arranged to definethe desired lumen shape of the catheter jacket 300. Similarly, thespacers 320 may have any suitable size and shape to define the desiredlumen shape of the catheter jacket 300.

While only a few different shapes are illustrated herein, many differentlumen shapes formed from two or more elongate substrates 310 iscontemplated herein. For example, the two or more elongate substrates310 may be combined to form cross-sectional shapes including oval,square, squircle, rectangle, triangle, diamond, trapezoid,parallelogram, hexagon, octagon, etc. It is noted that these shapesinclude variations of the shape including rounded corners.

As shown in FIG. 16 , the assembly having two or more elongatesubstrates may use a method 900 including the additive manufacturingprocess to define a non-cylindrical/non-circular lumen through catheterjacket formed by the additive manufacturing process. For example, themethod 900 may include feeding 902 two or more elongate substratesthrough a substrate channel in one or more heating cartridges. Thesubstrate channel may be in fluid communication with an interior cavityof the one or more heating cartridges. The method 900 may also includefeeding 904 a filament through a filament port into the interior cavityof the one or more heating cartridges and melting 906 the filament inthe interior cavity of the one or more heating cartridges. Further, themethod 900 may include moving 908 the one or more heating cartridgesrelative to the two or more elongate substrates at least in alongitudinal direction to form a catheter jacket including material fromat least the filament. Also, the method 900 may include removing 910 thetwo or more elongate substrates to define a non-circular lumen throughthe catheter jacket along the longitudinal direction.

In one or more embodiments, the method may also include inserting aplurality of spacers between the two or more elongate substrates. Eachspacer of the plurality of spacers may be spaced apart from an adjacentspacer of the plurality of spacers. In one or more embodiments, themethod may include covering or wrapping the two or more elongatesubstrates (and the spacers) with a liner prior to feeding and meltingthe filament.

In one or more embodiments, the method may include removing theplurality of spacers prior to removing the two or more elongatesubstrates. In other words, the spacers may be removed from the catheterjacket (e.g., after the catheter jacket is printed and formed) to makeit easier to remove the elongate substrates.

In one or more embodiments, the two or more elongate substrates may bepositioned relative to one another to define an oblong cross-sectionalshape. For example, the spacers may be positioned such that the elongatesubstrates are arranged on either side of the spacers (e.g., on opposingsides of the spacers).

In one or more embodiments, the two or more elongate substrates mayinclude a first elongate substrate and a second elongate substrate. Thefirst elongate substrate may define a cross-sectional diameter that isdifferent than a cross-sectional diameter of the second elongatesubstrate.

In one or more embodiments, the method may further include feeding anadditional filament (e.g., a second filament) through another filamentport into the interior cavity and melting the additional filament withthe filament to form the catheter jacket including material from atleast the first filament and the second filament. In one or moreembodiments, the method may also include adjusting a ratio of thefilament (e.g., a first filament) relative to the additional filament(e.g., a second filament) over a longitudinal distance to change a Shoredurometer of the catheter jacket over the longitudinal distance.

ILLUSTRATIVE EMBODIMENTS

While the present disclosure is not so limited, an appreciation ofvarious aspects of the disclosure will be gained through a discussion ofthe specific examples and illustrative embodiments provided below.Various modifications of the examples and illustrative embodiments, aswell as additional embodiments of the disclosure, will become apparentherein.

A1. An additive manufacturing system comprising:

-   -   one or more heating cartridges, each extending from a proximal        side to a distal side and comprising a substrate inlet port at        the proximal side and a substrate outlet port at the distal        side, each heating cartridge defining an interior volume and a        substrate channel extending through the interior volume from the        proximal side to the distal side, wherein the heating cartridge        defines a first filament port in fluid communication with the        interior volume to receive a first filament;    -   a heating element thermally coupled to each heating cartridge of        the one or more heating cartridges to heat the interior volume;    -   a filament handling system comprising one or more motors to feed        at least the first filament through the first filament port into        the interior volume;    -   a substrate handling system comprising:        -   a head stock comprising a distal clamp to secure a distal            portion of an elongate substrate, wherein the substrate is            positioned to pass through the substrate channel when            secured by the head stock; and        -   one or more motors to translate or rotate one or both of the            substrate when secured by the headstock and the heating            cartridge relative to one another; and    -   an intermediate component system positioned proximate the        heating cartridge and comprising one or more internal        components;    -   a controller operably coupled to the heating element, one or        more motors of the filament handling system, and one or more        motors of the substrate handling system, the controller        configured to:        -   control the one or more motors of the filament handling            system to selectively control the feeding of the first            filament into the interior volume;        -   activate the heating element to melt any portion of the            first filament in the interior volume;        -   control one or more motors of the substrate handling system            to move one or both of the substrate and the one or more            heating cartridges relative to one another in at least a            longitudinal direction to form a first elongate catheter            jacket around the substrate;        -   control the intermediate component system to deposit the one            or more internal components on the first elongate catheter            jacket; and        -   control the one or more motors of the filament handling            system to selectively control the feeding of a second            filament into the interior volume;        -   activate the heating element to melt any portion of the            second filament in the interior volume; and        -   control one or more motors of the substrate handling system            to move one or both of the substrate and the one or more            heating cartridges relative to one another in at least a            longitudinal direction to form a second elongate catheter            jacket around the first elongate catheter jacket and the one            or more internal components.            A2. The system according to embodiment A1, wherein the one            or more heating cartridges comprises a first heating            cartridge defining the first filament port in fluid            communication with the interior volume to receive the first            filament and a second filament port in fluid communication            with the interior volume to receive the second filament.            A3. The system according to embodiment A2, wherein the first            elongate catheter jacket comprises material from the first            and second filaments.            A4. The system according to embodiments A2-A3, wherein the            second elongate catheter jacket comprises material from the            first and second filaments.            A5. The system according to embodiments A2-A4, wherein the            intermediate component system is positioned proximate the            distal side of the first heating cartridge.            A6. The system according to embodiment A2, wherein the            second filament is the first filament.            A7. The system according to embodiment A1, wherein the one            or more heating cartridges comprises a first heating            cartridge defining the first filament port in fluid            communication with the interior volume to receive the first            filament and a second heating cartridge defining a second            filament port in fluid communication with the interior            volume of the second heating cartridge to receive the second            filament, wherein the second heating cartridge is            longitudinally spaced apart from the first heating cartridge            and the intermediate component system is positioned            therebetween.            A8. The system according to any preceding A embodiment,            wherein the first and second filaments comprise a same            filament material.            A9. The system according to any preceding A embodiment,            wherein the first and second filaments comprise a different            filament material.            A10. The system according to any preceding A embodiment,            wherein the one or more internal components comprise at            least one of a lumen, a pull wire, a liner, etc.            A11. The system according to any preceding A embodiment,            wherein the substrate outlet port defines one or more            cutouts and the first elongate catheter jacket comprises a            number of protrusions corresponding to the number of            cutouts, wherein the one or more internal components are            deposited between the protrusions.            A12. The system according to any preceding A embodiment,            wherein the substrate outlet port defines one or more            protrusions and the first elongate catheter jacket comprises            a number of channels corresponding to the number of cutouts,            wherein the one or more internal components are deposited            within the channels.            A13. The system according to any preceding A embodiment,            further comprising the substrate, wherein the substrate            comprises a lubricious coating, a liner, and a braid, and            the catheter jacket is formed around the braid.            B1. A method for additive manufacturing of an implantable            medical device, the method comprising:    -   feeding a substrate through a substrate channel in one or more        heating cartridges, the substrate channel in fluid communication        with an interior cavity of the one or more heating cartridges;    -   feeding at least a first filament through a filament port into        the interior cavity of the one or more heating cartridges;    -   melting the first filament in the interior cavity of the one or        more heating cartridges;    -   moving the one or more heating cartridges relative to the        substrate at least in a longitudinal direction to form a first        catheter jacket comprising material from at least the first        filament;    -   depositing one or more internal components on the first catheter        jacket;    -   feeding at least a second filament through a filament port into        the interior cavity of the one or more heating cartridges;    -   melting the second filament in the interior cavity of the one or        more heating cartridges;    -   moving the one or more heating cartridges relative to the        substrate at least in the longitudinal direction to form a        second catheter jacket around the first catheter jacket and the        one or more internal components, wherein the second catheter        jacket comprises material from at least the second filament.        B2. The method according to embodiment B1, wherein the first        filament is fed into and melted within the interior cavity of a        first heating cartridge of the one or more heating cartridges,        and wherein the second filament is fed into and melted within        the interior cavity of the first heating cartridge of the one or        more heating cartridges.        B3. The method according to embodiment B2, wherein the first        catheter jacket comprises material from the first and second        filaments.        B4. The method according to embodiments B2-B3, wherein the        second catheter jacket comprises material from the first and        second filaments.        B5. The method according to embodiment B2, wherein the second        filament is the first filament.        B6. The method according to embodiment B1, wherein the first        filament is fed into and melted within the interior cavity of a        first heating cartridge of the one or more heating cartridges,        and wherein the second filament is fed into and melted within        the interior cavity of a first heating cartridge of the one or        more heating cartridges, wherein the second heating cartridge is        longitudinal spaced apart from the first heating cartridge.        B7. The method according to any preceding B embodiment, wherein        the first and second filaments comprise a same filament        material.        B8. The method according to any preceding B embodiment, wherein        the first and second filaments comprise a different filament        material.        B9. The method according to any preceding B embodiment, wherein        the one or more internal components comprise at least one of a        lumen, a pull wire, a liner, etc.        B10. The method according to any preceding B embodiment, wherein        forming a first catheter jacket comprises defining one or more        protrusions extending from an outer surface of the first        catheter jacket, wherein the one or more internal components are        deposited between the one or more protrusions.        B11. The method according to any preceding B embodiment, wherein        forming a first catheter jacket comprises defining one or more        channels extending inward from an outer surface of the first        catheter jacket, wherein the one or more internal components are        deposited within the one or more channels.        C1. A method comprising:    -   feeding two or more elongate substrates through a substrate        channel in one or more heating cartridges, the substrate channel        in fluid communication with an interior cavity of the one or        more heating cartridges;    -   feeding a filament through a filament port into the interior        cavity of the one or more heating cartridges;    -   melting the filament in the interior cavity of the one or more        heating cartridges;    -   moving the one or more heating cartridges relative to the two or        more elongate substrates at least in a longitudinal direction to        form a catheter jacket comprising material from at least the        filament; and    -   removing the two or more elongate substrates to define a        non-circular lumen through the catheter jacket along the        longitudinal direction.        C2. The method according to any preceding C embodiment, further        comprising inserting a plurality of spacers between the two or        more elongate substrates, wherein each spacer of the plurality        of spacers is spaced apart from an adjacent spacer of the        plurality of spacers.        C3. The method according to embodiment C2, further comprising        removing the plurality of spacers prior to removing the two or        more elongate substrates.        C4. The method according to any preceding C embodiment, further        comprising covering the two or more elongate substrates with a        liner prior to feeding and melting the filament.        C5. The method according to any preceding C embodiment, wherein        the two or more elongate substrates are positioned relative to        one another to define an oblong cross-sectional shape.        C6. The method according to any preceding C embodiment, wherein        the two or more elongate substrates comprises a first elongate        substrate and a second elongate substrate, wherein the first        elongate substrate defines a cross-sectional diameter that is        different than a cross-sectional diameter of the second elongate        substrate.        C7. The method according to any preceding C embodiment, further        comprising:    -   feeding an additional filament through another filament port        into the interior cavity; and    -   melting the additional filament with the filament to form the        catheter jacket comprising material from at least the filament        and the additional filament.        C8. The method according to embodiment C7, further comprising        adjusting a ratio of the filament relative to the additional        filament over a longitudinal distance to change a Shore        durometer of the catheter jacket over the longitudinal distance.

Thus, various embodiments described herein are disclosed. It should beunderstood that various aspects disclosed herein may be combined indifferent combinations than the combinations specifically presented inthe description and accompanying drawings. It should also be understoodthat, depending on the example, certain acts or events of any of theprocesses or methods described herein may be performed in a differentsequence, may be added, merged, or left out altogether (e.g., alldescribed acts or events may not be necessary to carry out thetechniques). In addition, while certain aspects of this disclosure aredescribed as being performed by a single module or unit for purposes ofclarity, it should be understood that the techniques of this disclosuremay be performed by a combination of units or modules associated with,for example, a medical device.

In one or more examples, the described techniques may be implemented inhardware, software, firmware, or any combination thereof. If implementedin software, the functions may be stored as one or more instructions orcode on a computer-readable medium and executed by a hardware-basedprocessing unit. Computer-readable media may include non-transitorycomputer-readable media, which corresponds to a tangible medium such asdata storage media (e.g., RAM, ROM, EEPROM, flash memory, or any othermedium that can be used to store desired program code in the form ofinstructions or data structures and that can be accessed by a computer).

Instructions may be executed by one or more processors, such as one ormore digital signal processors (DSPs), general purpose microprocessors,application specific integrated circuits (ASICs), field programmablelogic arrays (FPGAs), or other equivalent integrated or discrete logiccircuitry. Accordingly, the term “processor” as used herein may refer toany of the foregoing structure or any other physical structure suitablefor implementation of the described techniques. Also, the techniquescould be fully implemented in one or more circuits or logic elements.

All references and publications cited herein are expressly incorporatedherein by reference in their entirety for all purposes, except to theextent any aspect directly contradicts this disclosure.

Unless otherwise indicated, all numbers expressing feature sizes,amounts, and physical properties used in the specification and claimsmay be understood as being modified either by the term “exactly” or“about.” Accordingly, unless indicated to the contrary, the numericalparameters set forth in the foregoing specification and attached claimsare approximations that can vary depending upon the desired propertiessought to be obtained by those skilled in the art utilizing theteachings disclosed herein or, for example, within typical ranges ofexperimental error.

As used herein, the term “configured to” may be used interchangeablywith the terms “adapted to” or “structured to” unless the content ofthis disclosure clearly dictates otherwise.

The singular forms “a,” “an,” and “the” encompass embodiments havingplural referents unless its context clearly dictates otherwise.

As used herein, “have,” “having,” “include,” “including,” “comprise,”“comprising” or the like are used in their open-ended sense, andgenerally mean “including, but not limited to.” It will be understoodthat “consisting essentially of,” “consisting of,” and the like aresubsumed in “comprising,” and the like.

Reference to “one embodiment,” “an embodiment,” “certain embodiments,”or “some embodiments,” etc., means that a particular feature,configuration, composition, or characteristic described in connectionwith the embodiment is included in at least one embodiment of thedisclosure. Thus, the appearances of such phrases in various placesthroughout are not necessarily referring to the same embodiment of thedisclosure. Furthermore, the particular features, configurations,compositions, or characteristics may be combined in any suitable mannerin one or more embodiments.

The words “preferred” and “preferably” refer to embodiments of thedisclosure that may afford certain benefits, under certaincircumstances. However, other embodiments may also be preferred, underthe same or other circumstances. Furthermore, the recitation of one ormore preferred embodiments does not imply that other embodiments are notuseful and is not intended to exclude other embodiments from the scopeof the disclosure.

The invention claimed is:
 1. A method for additive manufacturing of animplantable medical device, the method comprising: feeding a substratethrough a substrate channel in one or more heating cartridges, thesubstrate channel in fluid communication with an interior cavity of theone or more heating cartridges; feeding at least a first filamentthrough a filament port into the interior cavity of the one or moreheating cartridges; melting the first filament in the interior cavity ofthe one or more heating cartridges; moving the one or more heatingcartridges relative to the substrate at least in a longitudinaldirection to form a first catheter jacket comprising material from atleast the first filament; depositing one or more internal components onthe first catheter jacket; feeding at least a second filament through afilament port into the interior cavity of the one or more heatingcartridges; melting the second filament in the interior cavity of theone or more heating cartridges; moving the one or more heatingcartridges relative to the substrate at least in the longitudinaldirection to form a second catheter jacket around the first catheterjacket and the one or more internal components, wherein the secondcatheter jacket comprises material from at least the second filament. 2.The method of claim 1, wherein the first filament is fed into and meltedwithin the interior cavity of a first heating cartridge of the one ormore heating cartridges, and wherein the second filament is fed into andmelted within the interior cavity of the first heating cartridge of theone or more heating cartridges.
 3. The method of claim 2, wherein thefirst catheter jacket comprises material from the first and secondfilaments.
 4. The method of claim 2, wherein the second catheter jacketcomprises material from the first and second filaments.
 5. The method ofclaim 1, wherein the first filament is fed into and melted within theinterior cavity of a first heating cartridge of the one or more heatingcartridges, and wherein the second filament is fed into and meltedwithin the interior cavity of a first second heating cartridge of theone or more heating cartridges, wherein the second heating cartridge islongitudinally spaced apart from the first heating cartridge.
 6. Themethod of claim 1, wherein forming the first catheter jacket comprisesdefining one or more protrusions extending from an outer surface of thefirst catheter jacket, wherein the one or more internal components aredeposited between the one or more protrusions.
 7. The method of claim 1,wherein forming the first catheter jacket comprises defining one or morechannels extending inward from an outer surface of the first catheterjacket, wherein the one or more internal components are deposited withinthe one or more channels.
 8. A method for additive manufacturing of animplantable medical device, the method comprising: feeding a substratethrough a substrate channel in one or more heating cartridges, thesubstrate channel in fluid communication with an interior cavity of theone or more heating cartridges; feeding at least a first filamentthrough a filament port into the interior cavity of the one or moreheating cartridges; melting the first filament in the interior cavity ofthe one or more heating cartridges; moving the one or more heatingcartridges relative to the substrate at least in a longitudinaldirection to form a first catheter jacket comprising material from atleast the first filament, wherein forming the first catheter jacketcomprises defining one or more protrusions extending from an outersurface of the first catheter jacket; depositing one or more internalcomponents on the first catheter jacket, wherein the one or moreinternal components are deposited between the one or more protrusions;feeding at least a second filament through a filament port into theinterior cavity of the one or more heating cartridges; melting thesecond filament in the interior cavity of the one or more heatingcartridges; moving the one or more heating cartridges relative to thesubstrate at least in the longitudinal direction to form a secondcatheter jacket around the first catheter jacket and the one or moreinternal components, wherein the second catheter jacket comprisesmaterial from at least the second filament.
 9. The method of claim 8,wherein the first filament is fed into and melted within the interiorcavity of a first heating cartridge of the one or more heatingcartridges, and wherein the second filament is fed into and meltedwithin the interior cavity of the first heating cartridge of the one ormore heating cartridges.
 10. The method of claim 9, wherein the firstcatheter jacket comprises material from the first and second filaments.11. The method of claim 9, wherein the second catheter jacket comprisesmaterial from the first and second filaments.
 12. The method of claim 8,wherein the first filament is fed into and melted within the interiorcavity of a first heating cartridge of the one or more heatingcartridges, and wherein the second filament is fed into and meltedwithin the interior cavity of a second heating cartridge of the one ormore heating cartridges, wherein the second heating cartridge islongitudinally spaced apart from the first heating cartridge.
 13. Amethod for additive manufacturing of an implantable medical device, themethod comprising: feeding a substrate through a substrate channel inone or more heating cartridges, the substrate channel in fluidcommunication with an interior cavity of the one or more heatingcartridges; feeding at least a first filament through a filament portinto the interior cavity of the one or more heating cartridges; meltingthe first filament in the interior cavity of the one or more heatingcartridges; moving the one or more heating cartridges relative to thesubstrate at least in a longitudinal direction to form a first catheterjacket comprising material from at least the first filament, whereinforming the first catheter jacket comprises defining one or morechannels extending inward from an outer surface of the first catheterjacket; depositing one or more internal components on the first catheterjacket, wherein the one or more internal components are deposited withinthe one or more channels; feeding at least a second filament through afilament port into the interior cavity of the one or more heatingcartridges; melting the second filament in the interior cavity of theone or more heating cartridges; moving the one or more heatingcartridges relative to the substrate at least in the longitudinaldirection to form a second catheter jacket around the first catheterjacket and the one or more internal components, wherein the secondcatheter jacket comprises material from at least the second filament.14. The method of claim 13, wherein the first filament is fed into andmelted within the interior cavity of a first heating cartridge of theone or more heating cartridges, and wherein the second filament is fedinto and melted within the interior cavity of the first heatingcartridge of the one or more heating cartridges.
 15. The method of claim14, wherein the first catheter jacket comprises material from the firstand second filaments.
 16. The method of claim 14, wherein the secondcatheter jacket comprises material from the first and second filaments.17. The method of claim 13, wherein the first filament is fed into andmelted within the interior cavity of a first heating cartridge of theone or more heating cartridges, and wherein the second filament is fedinto and melted within the interior cavity of a second heating cartridgeof the one or more heating cartridges, wherein the second heatingcartridge is longitudinally spaced apart from the first heatingcartridge.